Magnoliae cortex and Magnoliae radix, which are the dried cortex and radix of perennial plant Magnolia officinalis REHD. et WILS and relatives belonging to Magnoliaceae, are known to have the effects of eliminating dampness and phlegm and promoting the circulation of “Gi”, and thus, treating the following symptoms: retention of dampness and acupuncture of the diaphragm; numbness in skin and vomiting and diarrhea; retention of undigested food; abdominal distension and constipation; and coughing caused by phlegm (See The State Pharmacopoeia Commission of the People's Republic of China, Pharmacopoeia of the People's Republic of China, Chapter I, 204, Chemistry Industry Pressing, Beijing). Also, Magnoliae cortex contains essential oils, such as a, b, g-eudesmol, magnolol, honokiol, tetrahydromagnolol, magnocurarin, obovatol, obovataldehyde, alkaloid, saponin, etc. A characteristic component of Magnoliea cortex was determined to be magnolol (Korea Pharmacopeia, 7th revised edition, pp. 782, The Society of Korean Official Compendium of Public Health, Korea Ministry of Health and Welfare).
In studies on the pharmacological effects of Magnoliea cortex, it was demonstrated in in vitro and animal tests that a water extract of Magnoliae cortex has an anti-allergic effect against immediate hypersensitivity reaction (Shin, T. Y., et al., 2001, Arch. Pharm., Res., 24: 249-255). Also, the known pharmacological effects of Magnoliae cortex include apoptotic effects (Park, H. J., et al., 2001, Arch. Pharm., Res., 24: 342-348), NO synthesis-inhibiting effects and TNF-a expression-inhibiting effects (Son, H. J., et al., 2000, Planata med., 66:467-471), antifungal effects (Bang, K. H., et al., 2000, Arch. Pharm, Res., 23: 46-49), mental health-promoting effects (Kuribara, H., et al, 1999, J. Pharm. Pharmacol., 51: 97-103), and skin cancer-inhibiting effects (Komoshima, T. et al., 1991, J. Nat. Prod., 54: 816-822).
Magnolol was demonstrated to have a powerful antioxidive effect (Li, C. et al., 2003, Bioorganic & Medicinal Chemistry, 11(17): 3665-3671; Ogata, M., et al., 1997, J. of the American oil Chemist' Society, 74(5), 557-562), the effect of preventing hepatocytes from being damaged by D-galactosamine (Park, E. et al., 2003, Planta Medica, 69(1): 33-37), an anticoagulation effect (Pyo, M. et al., Archives of Pharmacal. Research, 2002, 25(3), 325-328), an antifungal effect (Bang, K. et al., 2000, Archives of Pharmacal. Research, 23(1), 46-49), an anxiolytic effect (Maruyama, Y, et al., 1998, J. Nat. Prod., 61(1): 135-138), an acetyl-CoA inhibitory effect (Kwon, B., et al., 1997, Planta Medica, 63(6), 550-551), and a cholesterol absorption inhibitory effect (Zhao, C., et al., 1994, Huazhong Nongye Daxue Xuebao, 13(4), 373-377). In addition, the present inventors reported that magnolol has the effect of treating diabetic complications (Korean patent application No. 10-2003-39241).
A general method for separating magnolol according to the prior art is as follows.
Magnoliae cortex is extracted by maceration for 24 hours at room temperature, and the extract is filtered. The filtrate is concentrated under reduced pressure to obtain dark-brown methanol extract. The methanol extract is solvent-fractionated with benzene and water to obtain a benzene fraction. The benzene fraction is applied to a silica gel column and eluted with benzene and ethyl acetate (1:0˜5:1) to obtain fractions 1, 2 and 3. The fraction is applied to silica gel column and eluted with benzene and ethyl acetate (20:1) to obtain a fraction rich in magnolol. This fraction is applied again to a silica gel column and purified with benzene and ethyl acetate (20:1), thus obtaining a crude crystal. The crude crystal is recrystallized from ethyl acetate to obtain pure magnolol (study on standardization of quality of herbal medicines and materials, Korea Ministry of Health and Welfare, pp. 201-202, 1996).
However, this method has a problem in that it many process steps since after systematic separation, silica gel column chromatography is carried out at least three time to obtain magnolol as a crude crystal, which is then recrystallized.
In addition to this method, reported methods include supercritical fluid CO2 extraction (SFE) (Zhang, Z. et al., Zhongguo yiyuan Yapxue Zazhi, 21(7), 401-402, 2001), capillary electrophoresis (CE) (Zhang, H., et al., 1997, Analytical Letters, 30(13), 2327-2339) and the like. However, these methods require expensive equipment and are suitable only for the separation of a small amount of magnolol.
Magnolol separated as described above is a very expensive substance (WAKO no. 137-09081, Catalog 2004, pp. 1196) which is sold at 88,000 Won (Korean currency) per 20 mg by WAKO Co. Ltd., a standard reagent-marketing company in Japan. For this reason, it is uneconomic to use magnolol.
As described above, magnolol shows excellent effects in various views, but is expensive and requires a complicated method and expensive equipment for its separation. For this reason, there is still no report on the mass separation of magnolol. Thus, there is a need for a method allowing magnolol to be separated in large amounts by an economic and simple process.
Accordingly, the present inventors have conducted many studies on a method for separating magnolol, which does not require expensive equipment and at the same time, allows separation process steps to be minimized, thus significantly reducing separation time and cost. As a result, we found that magnolol can be separated from Magnoliae cortex or Magnoliae radix in large amounts, thus completing the present invention.